1. Field of the Invention
The present invention relates to the orthopaedic surgery art and more specifically to bone depth gauges.
2. Description of the Related Art
Installation of orthopaedic trauma reconstruction plates frequently require that holes be drilled through bones to allow the installation of screws that are used to restore the patient's natural anatomy. The depth of each hole must be measured so that the correct screw may be chosen to attach a support plate to the bone. Existing depth gauges used in re-sterilizable trays used for the operating room are usually far too expensive to discard after each use and are usually consigned to a hospital or surgical center. They are expected to be reused indefinitely.
Devices of this type, because of the long expected use, are typically machined, stainless steel or anodized aluminum with a stainless steel tip hook. This style of depth gauge has a hook that extends from the distal end of a tip and which is intended to hook on the opposite edge of a hole drilled through a bone to determine the bone depth. The tip is typically manufactured from a rod of steel and adds significantly to the cost of the assembly. The tip has a substantially round cross-section except for the distal end where there is a hook feature. The maximum width of the tip must be less than the diameter of the drilled hole so that it may be introduced into the drilled hole and hook the far edge of the hole. An outer housing telescoped over the tip is pushed forward and a mark on the housing indicates, on a graduated scale, the depth of the hole. Frequently, the depth gauge is removed from the bone and then read which adds the necessity for some kind of friction to hold the sliding members in position as it is withdrawn.
What is needed in the art, therefore, is an orthopaedic depth gauge in which the manufacturing costs of at least some of the components are reduced to the point that some of these may be made available as a single use item.